As a liquid discharge head serving as a liquid discharge apparatus, a type of head of changing pressure of ink in a pressure chamber, causing a flow in the ink, and discharging the ink from a nozzle, thereby discharging droplets has spread. Particularly, a drop-on-demand head has most spread in general. Incidentally, there are roughly two methods of applying pressure to ink. Namely, one is the method of changing the pressure of the ink by changing the pressure in a pressure chamber in response to a driving signal supplied to a piezoelectric material, and the other is the method of applying the pressure to the ink by generating air bubbles in the pressure chamber in response to a driving signal supplied to a resistor.
The liquid discharge head in which the piezoelectric material is used has adopted various kinds of methods. In these methods, a shear mode method which can be easily achieved comparatively by machining a bulk piezoelectric material has been often adopted. In the shear mode method, the piezoelectric material which has been polarized is shear-deformed by application of an electric field in its orthogonal direction. Here, the piezoelectric material to be deformed serves as a partition which is formed by processing ink grooves and the like on the polarized bulk piezoelectric material by using a dicing blade. An electrode pair (i.e., a pair of electrodes) is formed on both the sides of each partition to drive the piezoelectric material, and the liquid discharge head is finally constituted by forming a nozzle plate having nozzles thereon and an ink supply system (Patent Literature 1).
Besides, the liquid discharge head adopting the shear mode method has an advantage that restrictions on inks are relatively few and it is thus possible to selectively apply inks of wide-range materials to a recording medium. From this viewpoint, in recent years, an attempt to utilize the liquid discharge head for industrial applications such as color filter manufacturing, wiring patterning and the like has been often made. Moreover, to achieve further high-definition patterning, a smaller volumer per ink droplet to be discharged by the liquid discharge head has been required.